Buoyancy type liquid metering device



Oct. 21, 1952 w. c. STICKNEY 2,614,578

BUOYANCY TYPE LIQUID METERING DEVICE Filed Jan. 24, 1951 pRo caess IN VEN TOR. WILDER STICKNB'LY M ATTORNEY.

6 Sheets-Sheet 1 4 -Qct. 21, 1952 w. c. STICKNEY 2,614,578

- BUOYANCY TYPE LIQUID METERING DEVICE Filed Jan. 24, 1951 v 6 Sheets-Sheet 2 E E a 25 20 I /21 J' 'ECQ. 6. 1 .511 P INVENTOR. IL BNEY Z.; ATTOWEY 1952 w. c. STICKNEY 2,614,578

BUOYANCY TYPE LIQUID METERING DEVICE Filed Jan. 24, 1951 6 Sheets-Sheet I5 :h: q 35 11; L;

l L 55 )L INVENTOR.

/ wxppmz c. n ma) 51a 2' BY I ATTORN Y Oct. 21, 1952 w. c. STICKNEY BUOYANCY TYPE LIQUID METERING DEVICE 6 Sheets-Sheet 4 Filed Jan. 24, 1951 IN V EN TOR. IL ER c. s'Il BN- Y pyr ronwm Oct. 21, 1952 w. c. STICKNEY 2,614,578

BUOYANCY TYPE LIQUID METERING DEVICE Filed Jan. 24, 1951 6 Sheets-Sheet 5 C RELHY D RELAY FREJ- JAY 10 vacuum -i|- -H- TUBE 1 2 z CIRCUIT 6 mp2,

H RELEY MOTOR 21 SOLFJNOID AL E 1' INVENTOR. WlLDER c. TlCBNELY -H- CONTBC'I OPEN 1 minimum CONDITION y 44 CONTHCT 01.0521: 1N D-3SNR61ZED CONDITION ETTORNEY Oct. 21, 1952 w. c. STICKNEY 2,

v BUOYANCY TYPE LIQUID METERING DEVICE Filed Jan. 24, 1951 6 Sheets-Sheet 6 INVENTOR. WILDIE c. sTIcBN/ Y %.'p BTTORZNEY which result in errors.

Patented Oct. 21; 1952.

UNITED STATES PATENT OFFICE" BUOYANCY TYPE LIQUIDMET-EB'ING DEVICE Wilder C. Stickney, Penn Township, Allegheny County, Pa., assignor to Gulf Research 85 DevelopmentCompany,Pittsburgh, Pa.,'a c'orporation of Delaware Application January .24, 1951,;SeriaLN0.$207,635-

22 Claims.

This invention relates to a buoyancy type liquid. metering device, and more particularly to a metering device which is readily adaptable to weighing and/or dispensing a measured quantity of liquid and to measuring the rate of flow of a moving'body of liquid. v

Although there aremany methods ofweighingliquids, the buoyancy weighing method has many distinctive advantages. Among these'advantages is the fact that the buoyancy weigh ing method requires less capacity of weighing device in order to detect a balance, and therefore greater sensitivity is obtained. A further-advantage is that the buoyancy method eliminates conventional balance components such as beams,

pivots, counter-weights, levers and the like.

The buoyancy method of weighing makes use.

It is therefore possible to weigh a knownqu'antity of liquid by a veryelementary application I of this principle; such a device comprises a reservoir filled to the overflow point with liquid,

- a freefloatingposition of the floatandlforcausa float in the reservoir freely floating in the liqafiect the dimensions of the device as well as being measured, all of In addition, the use of a float which rises and falls substantially with variations in the level of liquid in the reservoir frequently. leads to operational difficulties.

It is an objectof my invention, therefore, to provide an improved buoyancy type liquid meterthe density of the liquid ing device which utilizes the'buoyancy principle of meteringin a novel manner withoutlthe disadvantages which attend. prior art devices of, similar character. A further object is topro-f vide a buoyancy type liquid metering device" which is capable of performing [an accurate metering operation without regard tothetemper'ature orjprjessure at which the measurement 'is conducted. Another object is to provide a device oi'the' character described hay-j ing' a flexibility that rendersit easily adaptable", for use in' weighing, in .the determination of flow rate and/or in dispensing. liquids of j all d escriptions. [Still another object of my, invention iS to provideian improved buoyancytype liquid. metering device which ,is fully, automatic, yet. safe for .use' in the .metering" of inflammable -materials. I

These and. other-objects are accomplished by my invention wherein I provide ameteringdevice .having a' reservoir provided .withinlet and outlet means,a 'float havinglajlimited vertical movement within' said reservoir in responsef; to Y thebuoyancy of reservoir liquid, means for temporarily fjapplying a predetermined'fdownward 'j force to said 'float'and means for sensing a. given f free floatingpfosition of said float;both with said and without said forceat a; lower "liquid level.

vidingmeans for introducing'liquid into the reservoirjtoestablish the liquid level therein'at in'g the prog-ressionof the liquid level Ito ,theotherdreefloating position of the fljoat, I thereby-meter a predetermined quantity-of liquid between the two free floating positions of the fioat, Myfinventionmayj-best beunderstoodbyrefere I enceto' the accompanying drawingsian'd the de- I scriptiveimatt'er :relating thereto". 1* Referring tor the'drawings, Figsfl and z-are diagrammatic sketches illusitrating my invention in itsbroadest'aspectand 1 showing the liquid-level-in thehigl' and low lever I siti ns. epe i Fi s i 3 a ar e mal i k t h s 155;

wme'fhish n w lev l siti is';jiuujstrat- 111g th in i eupon Which t ee i tion based; 7

Eig. s s 'uiagra'mmanc sketch .of a referriqi embodiment of my'inven'tion;

Fla. 6111s a j' dia ramm c et of embodim nt; v.

Fig.1.? is'a dia rammatic sketch of area; ferred'embodimentinmore'detail;

. bodiment showing the metering device without the complete control mechanism and without the top of the housing;

Fig. 9 is an elevation of the device shown in Fig. 8, taken partly in section along lin :9-9 of Fig. 8;

Fig. 10 is an elevation as in Fig. 9, partly in section, showing the high level float structure and the mechanism associated therewith;

Fig. 11 is a section taken along line llll of Fig. 10;

Fig. 12 is an elevation, partly in section, taken along line l2l2 of Figur 10, showing both the high and low level floats and the mechanisms associated therewith;

Fig. 13 is a schematic diagram of the electrical control circuit employed with the preferred embodiment described hereinafter;

Fig. 14 is a schematic diagram of the vacuum tube amplifier circuit employed in the control circuit of Fig. 13.

Referring to Figs. 1 and 2 which show the simplest form of my invention, 1 is a reservoir for measuring liquid 2 contained therein and is provided with valves 3 and 4, res ectively, in a communicating flow line for admitting and discharging liquid. A float 5 is situated within the reservoir by means of a diaphragm 6 which permits a limited vertical movement of the float in response to the buoyancy of reservoir liquid. The diaphragm, however, does not seal off liquid, but rather permits the liquid to be open to the atmosphere at all, times. A weight 1 is provided to te'mporarilyapply a downward force to the float 5 in order'to perform a metering operation.

It should .be, clear that for some particular liquid level, such as the high level shown in Fig. l, the system will be at equilibrium, such that the combined weight of the float and the applied weight I will be exactly counterbalanced by the buoyantforce of the liquid 2. This condition may be detected or sensed by means of a pointerB which registers on a scale 9 to show the balance point or the point at which the float and applied weight exist in a free floating position. It should also be clear that when weight 1 is removed from thefioat and liquid is partially discharged from'the reservoir, a second balance point Will exist when the liquid level has receded to such a point that the weight of float 5 is exactly counterbalanced by the buoyant force of the liquid 2', the float again existing in a free floating position. Such a position, with the liquid at the low level, is shown in Fig. 2. This second balance point also maybe sensed by means of pointer 8 and scale 9, and will be precisely at the same point on the scale as when the liquid is in the high level position. Since for any iven weight of Weight 1 a fixed quantity of liquid will be discharged from the reservoir, it is possible tocompute the weight of the liquid discharged and thereby meter out a predetermined quantity of liquid. Of course the device may be calibrated to perform the same function.; Thus, starting with an empty reservoir, valve 4is closed and valve 3 is opened, admitting liquid to the reservoir through the flow line until a high level balance point is reached with the weight ,1 applied to the float as in Fig. 1. At this point valve 3 is closed and valve 4 is opened, permitting liquid to discharge from the reservoir until a second or low level balance point is reached with Weight I removed from the float as in Fig. 2. At this point, a known quantity of 4 liquid will have been discharged from the reservoir and valve 4 may be closed.

It should be apparent that the procedure could be reversed and a metering operation conducted by causing the liquid level to progress from a low level balance point, as in Fig. 2, to a high level balance point, as in Fig. l; Employing such a procedure, liquid is admitted to the reservoir through valve t in the flow line until a low level balance point is reached without application of weight I to float 5. Then, by permitting further liquid to enter the reservoir until a high level balance point is reached with weight I applied to float 5, a known quantity of liquid will be introduced to the reservoir.

Computation of the weight of fluid which is metered between the two balance points may more readily be understood by reference to Figs. 3 and 4 which diagrammatically represent the system at the high and low level balance points respectively. In each figure the float is shown in a free floating position, as it exists at each balance point. The liquid which is metered is equivalent to that quantity of liquid which existed in the locus defined by the annular space between the float and the reservoir wall and by the difierential between the high and low level positions of the liquid; this differential volume of liquid is characterized by the shaded area in Fig. 3. Referring to Figs. 3 and 4,

w1=the weight which is alternately applied to the float wz=the Weight of the float Wm=the weight of the liquid being metered Vm=thevolume of the liquid being metered Azarea of the base of the reservoir a=area of the base of the float As stated, the application of Archimedes principle to floating bodies indicates that the weight of a floating body is equal to the weight of the displaced liquid. Thus, since the Weight of this liquid, in the case of Fig. 3, is hida and. in the case of Fig. 4, is hzda,

The weight of liquid metered, Wmzvmd, and since Vm=(h1h2)A(h1-h2)a, or

Then, since wl hsda, dividing through by hada gives 7 I V 1 n h dAh da Aa h da hm a device. -.In such amanner,

Ifthegig'eometry of the system is :suchthat A:2a,' it readilyzseenxthat the :weight of liquid being metered; "Wm;will. equal the weight 1101 which. is applied to-thefloat: for:each.measurement. j-It'is alsorreadilyuseen that the rmeasurement -is uni affected: by any givenrtemperat'ure of'rmeasure ment. and therefore, 'itis: ordinarily unnecessary to. compensate for this: temperature :by auxiliaryequipment-xor in-an'y calculations. :The: device of myri'nvention .will take a fluid of anyidensity aridxalmostany-temperature anddeliver an exact weight. :It: is necessary, ,however; that "the temperature of the liquididuring the Weighing period be held constant to insure a precise measurement. For all practical purposes, thiscmeans that if the fluidzis atwambient temperature no correction isrnecessary. On the otherjchand, if

the temperature of the fluid dilfers from ambient temperature, then an error proportional to the timegofmeasurementi andthetemperature differby; limiting themeteringzor weighing periodvso that the. temperature change is negligible. 'For example, "in .weighing gasoline it has been found that a minute or twovmayadvantageously: beemployedwithoutdevelopment of significant errors in :measurement fdue to temperature variation. However, under extreme conditions, it may be necessary .to add'a'heat interchanger between the sourceof fluid and the meteringdevice in 'order' to bring the temperature of the fluid 1 to the ambient temperature and reducethe error due to.the 1 temperature drift during weighing. IIt should-alsobexnoted in thisiconnection, that my device ;may be employed to meter a wide variety 3 -120 ence will appear. This-error can .be minimized of .fillidSvWlthOllt regard to ordinary i changes in barometric" pressure, unless extreme accuracy. is required. For all practical purposes, however,

i .so that v:liquid :may '-'be 'dischargedhthrough solenoid va-lve 13 faster than it "enters reservoir I when the valve is opened I after a metering period. The metering .'operation :is' then conyductedtfr'om .a lowfi level" balance point, without weight 1rapplied'toreceptacle 5,- as shown in Fig.6, to .a high level balance point, with. weight 1 applied :to the receptacle. Under ordinary conditions the liquid--level -.is imaintained approximately 'at' the low level balance point. or

slightly'therebelow by means of the solenoid valve l3-which' automatically. opens and closes to maintainuthislevel. -"When "it is desired to .measure the'liquid flowing through line I 2, a pushibutton switeh is mianually closed; this in turn'closes solenoid'valve .I3 and .permits the liquid to'rise in the reservoir: to fthe..lowsl'evel balance point and thereafterflto' the high level balance point.

These 'two balance points are detectedbysbah ance contacts Hl which, through the control circuit,. proceedto indicate either the time for a given weight of liquid which flowed between thetwo balancepoints, or the rate of' fiow of liquid 'fromthe process, whichever is desired.

Adiagrammaticsketch of theparticular embodiment of my inventionshown in Fig. 5. is also shown ;in.' more detail inv Fig. '7. -As shown :in

Fig. 7, the .liquidfflows'through solenoid valve l3 and conduit l 2 until it reaches a point :where it branches, part can passing through restriction ll leading toa -process and part of it-passing to reservoir l. Reservoir l'most'conveniently takestheform of a cylinder substantially-open atthetopiand connected :at the bottom to'con- :duit i2. -A housing Mfiisiprovided to -surround the reservoir for purposes of protection and to provide support for mounting further component parts which are suspended above the reservoir.

no correction isnecessary for barometric pressure,-as long as practical fluids of' appropriate density range are being metered. In-the preferred embodiment of my invention. as diagrammatically-shown in Fig. v5, I provide the above'described device witha pair of balance contactsg'enerally indicated at H] to electrically sense the free floating position of the float- 5 which takes-the form of a receptacle-adapted to receive :therein weight ,1. In this embodiment,

Balance contacts I0 are mounted on this'hous'ing. Thefioat 5 also convenientlywtakes the form or a cylindrical receptacle and is 'mounted at the top thereof by meansfi'of .a diaphragm B- rigidly the device is designed to meter-the flowin-to a process andtherefore. a -restriction l l is provided in the. flow line I2 feeding the process and reservoir |-to insure that liquid will be admitted :to

the reservoir faster than itcanbe-consumed by the process. .Insteadof such a restriction, a valve,

notshown, could be inserted inthe flow 1i-ne betweenthe reservoir'and the process to peri- *odicallyinterruptthe flowand thereby .accomplish-thesame result. As-shown in Fig. 5,3:5016- noid valve 13 isprovided to maintain the reservoir in a filled condition and-generally control the flow of .liquid thereto. An electrically operated control circuit, to be described hereinafter, is

providedto-automaticallyoperate and control the in thefiow .line betweemtheprocess andreservoir.

the flow of liquid into.

secured thereto and to the housing 14. .FI-he'float depends into reservoir Land is further guided 5 by a second idiap'hragm' lfia'fiixed to the base thereof andalso secured to .arigid icylindrical member 16 depending from the toptofi housing I4 w-ithinfloat 5. Inside. of member lt-"near 'ilts base there "is provided .a, plate lladapted to receivejweight T which rests. thereon. Weight "l is provided withran'eye zl fiadapted P receive a hookon rod .lfl'which extends into cylinder l6 forthe purpose of lowering 'andlelevating weight: 1. The top Mind 1 SJis hooked to an arm 20 which in turn is reciprocated by means of a motor 2| on housing .14, through "a :camld'rive 22 and pivot 23. Arm 2t isjrprovided with amercury switch 2'4 adaptedto :close when the'tarm and weight are elevated and 1 thereby indicate.

to the'control :circuit the. position of weight 1.-

The mechanicaldetails of this "device are-more completely .t-setvforth in Figs. "8' to 12. Referring to Figs.--8::and9, it isiseen.thatsubstantially the samestructuret is:.s-ho'wn-' as in Fig- '7. #Reservoir v l conveniently takes the form of an inverted bottomless bottle. provided with a neck-"'25- which is rigidlyssecured t a; smal1 thr e .25

by means'of-an annular ringil, a packing gland '28 :and a gasket 29. ri e :26 is :provided with threads to engage inlet: and outlet conduits and with a hole 30 which, together with neck .25.

of reservoir Lleffectively forms -an-inverted ":T connection.- Housing illis provided with :a base 3| uponwhich reservoir lreststhrougha'shock absorbent ring 32,..base .3 I being rigidly secured plate I? and into the boss.

to coupling pipe 26 by means of member 33. The entire unit may also be furnished with sup- 7 porting legs or a base such as 31a. The top of housing I 4 is provided-with a hinged lid 3% which.

permits access to the rigid cylinder it depending from the top of housing It, so that weight I may be changed when desired. The inside of housing a flange 49 which receives diaphragm 6, and.

another annular ring. fill bolted to flange ill, with diaphragm ,6 sandwiched therebetween, rigidly secures the diaphragm to the float. A similar arrangement likewisesecures diaphragm 5 to the base of float 5 and to the base of cylinder Hi. In this case the inner periphery of the diaphragm is sandwiched between the central portion of plate i? and a central boss within float 5, by means of a bolt 32 running through The outer periphery of diaphragm i5 is sandwiched between two annular rings 63 and M by means of bolts, ring '43 being rigidly secured to cylinder it. Thus float 5 is mounted in'a semi-rigid condition so that it isfree enough to move a slight distance in response to the buoyant force of liquid within reservoir [,yet secure enough to prevent substantial movement of the float, Advantageously, the distance float 5 is permitted to move may be aslittle as one sixteenth of an inch, or, just sufi'icient enough to operate balance contacts ill.

Both motor 2i and balance contacts ii) are rigidly secured to plate 35 and, as hereinafter described, are electrically connected to the control circuit. Balance contacts it are opened and closed in accordance with the slight movement of with an arm 53 to which a pin 54 is rigidly secured to transmit motion of the float to high level contacts .9, pin 54 also being rigidly attached to the lower contact of contacts 49. Low level float 48 is similarly suspended from a pair of rods 55 which in turn depend from a second arcuate member 56. Another pin 5,? is also rigidly attached to an arm 53 of member 56 and to low level contacts 5%. Members 52 and 56, as well'as plate 36, are all provided with holes to permit the free vertical movement of pins 54 and 5'! so that contacts 49 and 50 will open and close in response to the high and low level conditions of liquid in reservoir l.

The control circuit previously referred to is shown in Fig. 13. Preferably it is connected tov the conventional 110 to 115 volt source of alternating current and is fused and provided with a main switch as. As may be seen, a system of relays is provided to control the operation of the I metering device heretofore described. For convenience each relay is given a designation such as A relay, B relay and the like, and the contact of each relay is designated as A-i, A-2 and the like. The contacts for each relay are shown beneath each relay to illustrate the posi tion of each contact in the normal or deenergized condition of the relay, and all contacts in the circuit are shown in'the deenergized condition. Since direct current relays are employed herein, a rectifier 6| as well as a filter comprising resistance 52 and condenser 63 are provided to convert the alternating to direct current, and provide relays A, B, C, D and E with a source of power. Since it is desired to be able to employ the metering device with inflammable, as Well as nonflammable liquids, for reasons ofsafety,"the

float 5 by means of a pin &5 rigidly secured to the upper balance contact and to flange ii! and ring ti at the top of float 5. Pin 15 is shown in the broken section in Fig. 9 and in Fig. 12 and passes freely through hole 46 in plate 35. Therefore, as long as the liquid level within reservoir l is below a balance point, whether or not weight I is applied, balance contacts ill will remain closed. They will also be closed at the balance point, but when the liquid level is higher than that level which exists at a balance point, balance contacts it will open. These indications will be sensed by the electrical control-circuit and aiiect the operation of the device accordingly.

In order to indicate to an operator when the reservoir is full and when the liquid level is low,

suspended within reservoir l, as shown in Figs.

9, 10 and 12. These floats are operatively con-,

nected to high level and low level contacts 49 and 56, respectively, to operate indicator lights in the control circuit and thereby inform the operator of the condition of the reservoir. Both floats take the form of an annular ring of cor or other suitable material and need not float in the literal sense of the word, since the buoyant force of the liquid in the reservoir is sufiicient to give a proper indication even though both floats may be completely submerged. High level float ll is suspended from rods 51 which in turn are secured by means of hooks to an arcuate resilient member 52 rigidly secured and depending from the base of plateet. One end of member 52 is provided balance contacts, as well as the high and low level contacts, are isolated from the higher currents ordinarily employed in relay operation, by means of a vacuum tube amplifier circuit shown in detail in Fig. 14. Balance contacts it are thus designed to operate F relay, high level contacts 49 operate G relay and lowlevel contacts 513 operate I-I relay. Referring to Fig l l, it is readily seen that if the vacuum'tubes are biased at cut-off, no current will flow therethrough and hence the relay in each vacuum tube circuit will not operate. However, as soon as a pair of contacts close, the bias is reduced on the corresponding vacuum tube, permitting conduction through the plate circuit and hence operation of the relay. Thus, closing of balance contacts ill will result in the conduction through vacuum tube 6 3 and the energizing of relay F. Similarly, closing of high level contacts 69 will energize relay G, and closing of low level contacts 50 will energize relay H. Relays G 1 and H simply close contacts Gi and H4 respectively, when energized, and the only function of these contacts is to operate lights 51 and 58,'

which simply indicate high and low level conditions. Since these lights do not affect the operation of the remainder of the control circuit; the

high level and low level contacts as well as relays G and H may be disregarded.

Relay D, which controls the operation of solenoid valve 13 through contact D4, is provided start, is provided with a field condenser 70. An-

other condenser H and resistance 72. are also provided across contacts E-l, E-2, A-S'and A4 to 9 preventarcing; A similar' network consisting' of resistance-'13'andcondenser -H isprovided across contactD l to prevent arcingx-and light'fi is providedacross solenoid valve 1 3 I10 indicate'when thesol'enoid'valve is ,energiz'ed andfthe reservoir is fillings A- cloclr- 1 6- is'also providedto indicate the time elapsed between the high level and-low lever balance-points during a m'eteri-ngoperation.

Iii 'a'ddi'tiOn; push butto'nTTis provided-to initiate a weighingor metering cyclewhi'chis automatically-performed; by- -means-of 'thecontrol cir'cuit.

Broadly'stated; the operationof 'the '-*emb'odiment' specifically described -*is as follows-z Itis recalled" that thedevice inthis embodiment is placed'iwtlie'imet-conduit leadingto a process which is consuming liquidat a rate cont-rolled by the 'process; The 'metering of the gasoline consumption of an internal combustion 'test engine is illustrative' of I such an applicati'on of my device; As shown in Fig; 5; the liduidw-i-ll be con trolled by solenoid "valve 1 3 'which'; in" the initial stage-*of -operation; I maintains 'a full reservoirin the' meter-ing'device. The wei-g-ht 1; is" applied? to receptacle 5 di1ringthis phase of operation.- Balance eontacts l then assure that suni'cient: liquid will b'e introduced' to the reservoir through valve [3 o =refill thereservoineach time the liquid level-*dropsto the high level balance point-therebyclosing -the balance contact'st- Balance-" con- I tacts== lfl li cont'rol the operation '0f F relay= and; throng 'contact-"F-lfi also control th' operation of n relaymhich' must be ene rgized to open" solenoid valve l 1 The time -delay *condenser*-69 acrossD'relay'is provided to insurethata slight excess 'ofliquid will I be-introduced to the reservoir and thus maintain the I liquid level therein slightly above the high levelbalance-point when the device is' -no't performing a metering operamom. Thus, as the process constantly consumes the -liquid in reservoir 1; causing the-liquid level P to irecedel' valve I 3'-*will penperiOdicaHY to admit more liquideach time the high' level' balance point is reachedi Assuminga full condition inreservoir-1 push button 11 is th'en depressedito initiatea metering-= cycle. This permits the liquid level" tc recede toithe-high level baIance -pOintas the processconsumesismorei-liqnid and the relay circnit assures thatsxvalveril icwill? not open duringthemetering cycle-.1 Asusoom asztheihigh level-=5 balancepoint I ist reached Land 'ba-lanc'e: contacts-'- lfl cl'o'sm the metering cyclesbegins; weight T still bein'g applied toe-sfioatzt-ortreceptacle .52: Atthis point time a numben'of events simultaneously occurw The relaiyicii'cuitvcauses motor 121' to be energized and;

thereby elevate weight "1 5 removing: the force I of the. weight fromzthesfldat: and permitting :balance contacts Illto ;open;"v The: circuit also causes clock 'lfirto'. start 5a that: the time between the high and: low: level aha-lance points. may be observed. Motor-124r will. continue to elevate weight 'l *until switchi & on' arm': 20 of the: motor 'closesyathereby causing the: motortozstop, 4MeanwhileFthe'liquid withinsthareservoir. I has. continued-to Meade and. will further: 'recede .until itrirea'chesi a low I 10 weightlof liquid is thus displacedifrom reservoir l between thetime contacts ll close "with weight 1 down and the time I contacts I I0 close with weight I suspended. Flow-rate may then be computed from the 1 time it" takes a predetermined weight 'ofliquid topass out of the reservoir. Furthermore,, clockTGL-mayxbe calibrated for any known weight of weight-1'to'indicate directly the flow rate if desired.

The detailed operation of: the control circuit is presented hereinafter: nrouume form for purposes of clarity, since aipurely-verbal description of its!operationisrather difiicult to follow. In this outline, fourrbasic: phases of operation are 'setforth. Specifically;they are (I) the reservoir empty and initial energization of the electrical circuits-with theffilling' of the reservoir; (II) maintainingsra full-reservoir when not weighing or" metering, (III) the .weighing cycle through operation of the pushbiitton H; and (IV) again I maintaininga afnlfreserifoir as in- (II). An attempt has been made in the outline to set forth the operationofall elements 'in the appropriate time sequence. wherever? possible;

I Condition: Reservoiri:emptyi: Balance ifioat and weight down and balancecontacts closed. 1

Operations; Mni'nfswitch is turned on.

1. Relay F energized F closes A relay: energized (B A: and F closed) A closesw-(m'akes before A breaks) Holding, contact fore relay A :opens Noimm'ediate effect A closes-.Starts=i motor 21 to raise weight? A -.op ens+-No immediate effect A =closes:'-Iiming clock 76 starts but I ser-ves z no fiii'nction F ':closes--No-immediate effect F closess -Noimmediate effect 2. Switch'z24 on motor:.21.closes when weight 7 elevated... I

E relay energized-n E closes-No*imm1ediate effect E5 opens.''S-tops motor 21 E closes Bwrelay energized Ba '0pen's..A relay deenergized A opens-No immediate effect A c1oses-No immediate effect A opensNo immediate effect A.,, closes-Motor 21 starts to lower weight 7 since E closed A; opens-Cl0ck 76 stops closesI-Iolding contact for B relay BFcloses- D relay energized D1c1'osesValvc 13 opens and liqnidtadmitted to reservoir. 3.- Switch: 24:0! motorr21 opens when weight 7 lowered. v E relay 'deenergized:=

' E 'opens1\iot0rr21 stopped with Weight loweredv E closesNo immedi ate effect E3 opens-9N0: immediateveffct 4. Reservoir: becomes: filled carusing balance contacts 10 to openz I F. relayr deener-grized E open sNo immediate effect F opens-D relay deenergized after time delay: due to'condenser 69 D opens:Solenoid valve 13 closes F lopens'No immecliate effe'ct II llIa-intaining .ful-L :reservoir'when 'not weighing Condition Reservoirfilledabove level required to buoy fioat'andi liquidt'is being withdrawn B relay in? energized condition 13 open (A relay'can't operate) B -c1osed"('comp1etes circuit through C for B r l y I B 'closed"( completes circuit for D relay" when F5 closed) 1. Balance contacts close when levelrecedes to balance point with weight down. 7

F- relay energized F closes.-No immediate effect F -closesD relay energized D c1oses Solenoid"valve to admit more: liquid 1. F closesNo immediate etfect-v 2. Balance'contacts'fopen' when levelrises abo've balance point with Weight down. F relay deenergiz ed F opensNo immediate effect.- Fy'opens D' relay 'deenergized D opens.-Solenoid valve- I3 c loses F opens-No immediate effect 13*" opens III Push button Weighing cycle Condition: Reservoir filled above balance point; B

relay energized with B open, B .and B closed 1. Push button closed I C relay energized momentarily until push button released v 1 opensB relay deenergized B closes-No effect until F closed 13 opensNo immediate efrect B3 pensD relay and solenoid valve cant operate C closesNo immediate effect since F1 Open C closesNo immediate effect since Fa open 2. Balance contacts close when liquid recedes to first balance point,

F relay energized A relay energized siiice A and B are closed A closes (makes b e f 0 r e A breaks)Holding contact for A relay v A opens-No immediate effect since A1 is closed A closes-Weight motor 21 starts to raise weight 7 since E is closed A; opensNo immediate effect since E open A c losesTiming clock 76 starts F closesNo immediate effect since 13:;

open F closesl zo immediate effect since C3 open 3. lVeight elevated by Weight motor as liquid recedes (a) Balance contacts open F relay deenergized I F opensNo immediate effect since A holds A relay F opens-No immediate eifect since B open F opensNo immediateeffect since C3 open (b) Switch 24 closes when weight fully elevated E relay energized E closes-No immediate effect because A open E opens-Cuts ofi weight motor 21 E c1osesNo immediate effect until F closes 4. Balance contacts 10 close at second balance point with liquid receded F relay energized F closes-Completes circuit through E to energize B relay B opens A relay deenergized A opensNo immediate effect-only holding contact A closesNo immediate effect since B open A opensN0 immediate elfect since E open A closesWeight motor 21 A starts since E closed 6 5 1 opensliming clock ops B closesKeeps B relay energized B closesD relay energized since F closed D closed and solenoid valve 13 opened F closes-Permits D relay to operate when B closed F closesNo immedate eifect since 0;;

open 5. Weight motor through cam returns Weight to rfloat: Switch 24 then opens E relay deenergized E opensNo immediate effect E closes-No immediate effect since A open E opensN0 immediate effectl3 relay already energized 6. D relay remains energized until reservoir refilled and balance contacts are again closed.

F relay deenergized F opensNo immediate effect F 3pensD relay deenergized after time elay D opensSolenoid valve 13 closes F opens-No immediate effect IV Reservoir filled and balance contacts maintain in filled condition until next push button cycle.

It should be understood from the above outline that although high and low level indicator lights are furnished, they are dispensable since it is not necessary to know that the reservoir is in a filled condition to initiate a weighing or metering cycle. For example, if the liquid level in reservoir I has dropped so that the solenoid valve I3 is admitting liquid, push button I? may still be employed to start the weighing cycle. This will energize relay C, opening contact C1 and closing contacts C2 and Cs. Since balance contacts It will be closed, relayv F will be energized and thus close contacts F1, F2 and F3. With contact Fa closed, relay C will hold itself through contact C3. Transfer contacts 01 and C2 continue .to hold-relay B closed through contact Fi. As soon as the reservoir is filled, causing the balance contacts to open again, relay F will be deenergized. This will open contacts F1, F2 and F3. Contact F1 releases relay B. Contact F2 deencrgizes the relay D circuit and contact F3 deenergizes relay C. Relay D, after a time delay opens contact D1 which in turn opens the solenoid valve circuit. All relays are now deenergized and the Weighing cycle as set forth in outline form will automatically be initiated as soon as the level of liquid in reservoir I recedes to the high level balance point, closing balance contacts Iii.

As has been stated, my invention is not limited to the specific embodiment described for metering into a process, but may also be readily adapted to metering out of a process by an arrangement again pointed out that the metering operation would be from .a low level balance point with weight I suspended to a high level balance point with Weight 'I applied to the float. This would require only a slight modification in reversing the balance contacts I 0, as in Fig. 6. The only other modification would be reversal of the operation of mercury switch 24 so that motor 2| would suspend weight'l for the first, orlow level, balance point and lower weight I for the second, or high level, balance point. Furthermore, by simply providing an addition valve, the device described herein may be easily adapted to perform a dispensing operation. For example, a fully automatic dispensing device would be made by simply replacing clock It with another solenoid operated valve. Then under normal conditions liquid would always be retained in the reservoir, but the additional solenoid valve would permit one to dispense a measured quantity of liquid each time the push button were depressed. Of course such a valve could be employed in addition to clock I6 by further obvious modifications.

Further modifications should be apparent to those skilled in the art; For example, the float could take any variety of shapes or forms and an increased sensitivity may be obtained by employing a specially designed float cylinder. The float may also be supported by its own buoyancy or with the aid of a spring or counter-balance, as should be readily understood. In addition many equivalents may be employed in place of the diaphragms for mounting and guiding the float within the reservoir, such as fiexure pivots, movable arms, sliding bearings and the like.

In addition to those advantages which attend the use of a buoyancy type meter over other type of meters, as pointed out, my invention has further advantages not to be found in ordinary buoyancy meters. The fact that under ordinary conditions the device is relatively unafiected by temperature and pressure changes should make it readily apparent, that my invention has wide utility and greater sensitivity than other devices of a similar type. Furthermore, the utility of the device is greatly enhanced by its flexibility since the basic principle of my invention can be employed to advantage in such a wide variety of applications. Many devices of the same type require flexible connections or siphon tubes but my device may be connected rigidly into a system without such paraphernalia. The reservoir size ,13 can also be madetosuit various processes over a widerangeof capacities and corrosive fluids can be metered by such a device as I have described as longas provision is made to keep corrosive vapors away from the control mechanisms.

My invention is therefore limited only by the scope. of the claims hereinafter made.

I claim:

LA buOyancy type liquid metering device com- I prising a reservoir and a liquid flow line incommunication therewith, a float having a limited -1vertical movement within said reservoir in res-ponseto the buoyancy of reservoir liquid, means ,for temporarily applying a predetermined downward force to said float, means for sensinga free i floating position of said float, both with said forceapplied at one liquid level and without said forceiat a lower liquid level, means in the liquid flow line forcontrolling the accumulation of liquid in said reservoir to establish the liquid level therein at a free floating position of said float and for causing the progressionof the liquid level to the other free; floating position of said float, whereby the predetermined quantity of liquid between the free floating positions of said float maybe metered;

prising a reservoir providedwith inlet and outlet 2. A buoyancy typeiliquid metering device comprising a, reservoir anda liquid flow line in communication therewith, a float having a limited vertical movement within said reservoir in re- 'sponse,=to the buoyancy of reservoir liquid, a weight for temporarily applying a predetermined downward force to said float, means for sensing aifree floating position of said float, both with said weightapplied at one liquid level and with- P out said'weight at a lower liquid level, means op- BIZZLtlVBlY-CODHOHBG. by said sensing means. for ,icausing the introduction of liquid into said reservoirfrom said flow line to establish the -liquid level in said reservoir at a free floating position of said float-and for causing the progression of the liquid level to the other free floating position arenaer, whereby the predetermined quantity of liquid between the free floating positions of fsaid float mayibe metered. w 3. A buoyancy type liquid metering device comprising a reservoir provided with inlet and outlet means and a liquid flow line in communication therewith, a float having a limited vertical movem'ent within said reservoir in response to the.

buoyancy of reservoir liquid, a weight for temwiporarilynapplying a predetermined downward forcexto saidfloat, a pair of electrical contacts -operatively controlled by ,said float for sensing a; f -r-ee floatingqposition of said float, both with said weight applied at one liquid level and without said weight ata lower liquid level, means in saidhliquid flowline operatively controlled by f contacts for causing the introduction of 1" intosai'd rese'rvoirto a liquid level therein ""a a free floatin'gposition of said float and for causing theprogression of'the liquid level to the 'oth'erfree floating position of said float, whereby thepredeterminedquantity of liquid between the freefloating positions of said float may be f-metered. I

. ;,4..Aibuoyancy type liquid meterin device-com- ;jziprising aireservoir provided with inlet and outlet 1 means-,nndflaf jliquid; Iflow line communicating therewith, a; floatiwithin said reservoir, diarasmmeansbetween said float and said reseroir giving saidfioat, a limited vertical movement within said reservoir in response to the buoyancy p of reservoir liquid, aweight for temporarily applying a predetermined downward forceto said of said float, both: with; said weightapplied at one liquid level ;andwithoutsaid; weight-at a lower liquidlevel, means in said liquid flow line operatively controlled by said contacts for-caus ing the introduction of ,liquidintosaidreservoir to a liquidlevel therein at a free floating, posi- 131011 of said float and for causing the progression of the-liquidlevel to the other free floating po-v sition of said, float, whereby the predetermined quantity of liquid between, the free floatingpositions of said floatmay be metered, j

5., A buoyancy type liquid meteringdevice .com-

means, a liquid flow; line communicating therewith, a receptacle forming a float {within said reservoir, diaphragm means between said recepta cleand said reservoir giving a limited vertical movement to said receptacle within'said reservoir in response to the buoyancy of reservoir liquid, a

out said weight at a lower liquid level, means in said liquid flow line 'oper-atively controlled by 'saidcontacts for causingthe introduction; of

' quantityiof liquid between the free fioatingposimovement to said receptaclewithin said reservoir in response to the buoyancy of reservoirliquid, a-weight for temporarily applying a predetermined'downward force to said receptacle and a motor having a driving connection withsaid weight for actuating the same, a pair of electrical. contacts operatively controlled b said receptacle, for sensing a free floating positionofsaid receptacle, both with said weight applied at-one liquid level and without said'weight at a'lower liquid level, means in said flow line'operatively controlled by said contacts for causingthe in- .troductionof liquid into said reservoir to establish a liquid level therein at a free floating position of said receptacle and for causing'aprogression of the liquid level to the other free floating position of said receptacle, and meansresponsive to said electrical contacts for performing a function in proportion to the time interval elapsing between the respective free floating positions of saidreceptacle. a

7; A buoyancy type liquid metering device comprising a reservoir and a flow line communicating therewith for the 'introductionand with- 'drawalof'liquid, areceptacle forming a float predetermined downward force to said receptacle and a motor having a driving connection with said weight for actuating the same, a pair of electrical contacts operatively controlled by said receptacle for sensing a free floating position of said receptacle, both with said weight applied at one liquid level and without said weight at a lower liquid level, means in said flow line operatively controlled by said contacts for causing the introduction of liquid into said reservoir to establish the liquid level therein at a free floating position of said receptacle and for causing the progression of the liquid level to the other free floating position of said receptacle, and a timing mechanism responsive to said electrical contacts for exhibiting a function in proportion to the time interval elapsing between the respective free floating positions of said receptacle.

8. A buoyancy type liquid metering device comprising a reservoir provided with inlet and outlet means, a valve for regulating the flow through said inlet means, a float having a limited vertical movement within said reservoir in response to the buoyancy of reservoir liquid, means for temporarily applying a predetermined down- 'ward force to said float, means for sensing the free floating position of said float as the level of liquid in the reservoir recedes, first with said force applied at one liquid level and again with said force removed at a lower liquid level, means responsive to said sensing means for operating said valve to maintain a body of liquid in said reservoir under static conditions and to interrupt inlet flow during a metering operation.

9. A buoyancy type liquid metering device comprising a reservoir provided with inlet and outlet means, a valve for regulating the flow through said inlet means, a float having a limited vertical movement within said reservior in response to the buoyancy of reservoir liquid, means for temporarily applying a predetermined downward force to said float, means for sensing the free floating position of said float as the level of liquid in the reservoir recedes, first with said force applied at one liquid level and again with said force removed at a lower liquid level, means responsive to said sensing means for operating said valve to maintain a body of liquid in said reservoir under static conditions and to interrupt inlet flow during a metering operation, and means also responsive to said sensing means for performing a function in proportion to the time interval elapsing as the liquid level recedes between the respective free floating positions of said float.

10. A-buoyancy type liquid metering device comprising a reservoir provided with inlet and outlet means, an electrically responsive valvefor regulating the flow through said inlet means, a float having a limited vertical movement within said reservoir in response to the buoyancy of reservoir liquid, means for temporaril applying a predetermined downward forceto said float,

outlet means, an electrically responsive valve for regulating the flow through said inlet means, a float having a limited vertical movement within said reservoir in response to the buoyancy of reservoir liquid, means for temporarily applying a predetermined downward force to said float, a pair of electrical contacts operatively controlled by said float for sensing the free floating position thereof as the level of liquid in the reservoir recedes, first with said force applied at one liquid level and again with said force removed at a lower liquid level, means responsive to said electrical contacts for operating said electrically responsive valve to maintain a body of liquid in said reservoir under static conditions and to interrupt inlet flow during a metering operation, means also responsive to said electrical contacts for performing a function in proportion to the time interval elapsing as the liquid level recedes between the respective free floating positions of said float, and means for actuating said device to meter a measured quantity of liquid;

12. A buoyancy type liquid metering device comprising a reservoir provided with inlet and outlet means, an electrically responsive valve regulating flow through said inlet means, a float within said reservoir, diaphragm means between said float and said reservoir giving said float a limited vertical movement within said reservoir in response to the buoyancy of reservoir liquid, a weight for temporarily applying 'a predetermined downward force to said float, a pair of electrical contacts operatively controlled by said float for sensing the free floating positions of said float as the level of liquid in the reservoir recedes, first with said weight applied at one liquid level and again without said weight at a lowerliquid level, means responsive to said electrical contacts for operating said electrically responsive valve to maintain a body of liquid in said "reservoir under static conditions and to interrupt inlet flow during a metering operation, means also responsive to said electrical contacts for performing a function in proportion to the time interval elapsing as the liquid level recedes between the respective free floating positions of said float, and means for actuating said device to meter a measured quantity of liquid.

13. A buoyancy type liquid metering device comprising a reservoir provided with inlet and outlet means, an electrically responsive valve for regulating the flow through said inlet means, a float within said reservoir and adapted to receive a weight, a diaphragm between said float and said reservoir giving said float a limited vertical movement within said reservoir in response to the buoyancy of reservoir liquid, a motor operated weight for temporarily applying a predetermined downward force to said float, a pair of electrical contacts operatively controlled by said float for sensing the free floating position thereof as the level of liquid in the reservoirrecedes, first with said weight applied at one liquid level and again with said weight removed at a lower liquid level, means responsive to said electrical contacts for operating said electrically responsive valve to maintain a body or" liquid in said reservoir under static conditions and to interrupt inlet flow during a metering operation, a timing mechanism also responsive to said electrical contacts for exhibiting a function in proportion to the time interval elapsing as the liquid level recedes between the respective free floating positions of said ation.

I 1 floairiand electrical means'slfor?actuating said-gueviceto meter 'azmeasur'e'd 'quantityofiliquid; 1

I IAl A;:;buoyancy.ltype *liqui'dimeteringii.device comprisingslaz reservoir: provided wltht: rinletra-nd outlet meansaa solenoid valvefor regulatin'gs the flow throughs.saidiinlet means; a=second solenoid valve saidoutlet means; a cat within v said reservoir andLa-daptedfto receiv =a weight; a diaphragm between said float" an'd saidreservoir giving said neat a limited vertical movement.

outlet flow-' during a metering. operations and means foriactuatingxsaid device to meteri a mea's' ured quantitypfliquid; i 1 IS; A abuoyancy type liquid metering"=devic'e comprising a reservoir provided witiiinleti and liquid in theres'ervoi'r recedes; first with said I weight applied at oneliquid-leveL and again with said weight removed at a lowerliq-uidilev'el; means responsive: to said electrical;- contacts' 1 for oper atingthe first said solenoid valve to maintain a,

body'of liquid in said reservoir .under stati'c1..con'- ditions'andi'to interruptinletflfowduring a'Lmeteroperation, said means also" operating said second solenoid valve to dispense a measured quantity of liquid during a metering operation,

and electrical means for actuating said device to meter and dispense a measured quantity of liquid.

15. A buoyancy type liquid metering device comprising a reservoir provided with inlet and outlet means, a valve for regulating the flow through said outlet means, a float having a. limited vertical movement within said reservoir in response to the buoyancy of reservoir liquid, means for temporarily applying a predetermined downward force to said float, means for sensing the free floating position of said float as the level of liquid in the reservoir rises, first without said force applied at one liquid level and again with said force applied at a higher liquid level, means responsive to said sensing means for operating said valve to maintain a body of liquid in said reservoir under static conditions and to interrupt the outlet flow during a metering oper- 16. A buoyancy type liquid metering device comprising a reservoir provided with inletand outlet means, an electrically responsive valve for regulating the flow through said outlet, means, a float having a limited vertical movement within said reservoir in response to the buoyancy of V reservoir liquid, means for temporarily applying a predetermined downward force to said float, means for electrically sensing the free floating position of said float as the level of liquid in the reservoir rises, first without said force applied at one liquid level and again with said force applied at a higher liquid level, means responsive to said sensing means for operating said valve to maintain a body of liquid in said reservoir under static conditions and to interrupt the outlet flow during a metering operation.

17. A buoyancy type liquid metering device comprising a reservoir provided with inlet and outlet means, an electrically responsive valve in said outlet means for regulating the flow therethrough, a float within said reservoir and adapted to receive a weight, a diaphragm between said float and said reservoir giving said float a limited vertical movement within said reservoir in response to the buoyancy of reservoir liquid, a weight for temporarily applying a predetermined downward force to said float, means for electricallv sensing the free floating position of said outlet means; a solenoid operated valve: forregulating the flow-through said outlet means; a' float within said reservoir an'd adapted to receive'a weight, a diaph-ragm between said float'and said reservoirgivingsaid floatalimited vertical move ment within said reservoir in" response to the buoyancyof reservoir liquid, a motor operated weight for temporarily applying a predetermined downward force to said float, a pain'of electricalcontacts operatively controlledby said float for sensing the free floatingpositioriof said float as thelevel of liquid in the 'rese'rvoir rises, first without said weight applied at one liquid level and again with said weight applied at a higher liquid level, electrical means responsive to said electrical contacts for operating said solenoid valve to maintain a body of liquid in said reservoir under static conditions and to interrupt outlet flow during a metering operation, a timing mechanism operatively controlled by said electrical contacts for exhibiting a function in proportion to the time interval elapsing as the liquid level rises between the respective free floating positions of said float, and means for actuating said device to meter a measured quantity of liquid.

19. A buoyancy type liquid metering device comprising a reservoir provided with a conduit to admit and discharge liquid, a receptacle within said reservoir forming a float therein, a member rigidly secured with respect to said reservoir and depending into said receptacle, a diaphragm between said member and said receptacle giving said receptacle a limited vertical movement within said reservoir in response to the buoyancy of reservoir liquid, a removable weight within said member for applying a downward force to said receptacle, means for applying said weight to said receptacle and for removing the same therefrom, and means for sensing the free floating position of said receptacle both with and without said weight applied as the level of liquid within said reservoir is varied.

20. A buoyancy type liquid metering device comprising a reservoir provided with a conduit to admit and discharge liquid, a receptacle within said reservoir forming a float therein, a member rigidly secured with respect to said reservoir and depending into said receptacle, a diaphragm between said member and said receptacle giving said receptacle a limited vertical movement within said reservoir in response to the buoyancy of reservoir liquid, a removable weight within said member for applying a downward force to said receptacle, a motor having a driving connection with said weight for applying said weight to said receptacle and for removing the same 21. A buoyancy type liquid metering device comprising a reservoir, a flowline communicating therewith and providing an inlet and outlet means therefor, a floathaving a limited vertical movement within said reservoir. in response to the buoyancy of reservoir liquid, means for temporarily applying a predetermined downward force tosaid' float, means for sensing the point at which the total downward fore-e exerted-by the float is exactly counterbalanced by the buoyant force of the reservoir liquid, both with said force applied to said float at one liquid level and without said force at :a lower liquid level, and means in said flow line forcontrolling liquid flow and thereby altering the volume of liquid within said reservoir to establish such a point of balance with and without said force applied to said float, whereby the predetermined weight of liquid as defined by the differential volume of liquid between successive points of balance may be metered.

22. A buoyancy type. liquid metering device comprising a reservoir, a liquid flow linein communication therewith, afloat having a limited vertical movement within said reservoir in response to thebuoyancy of reservoir liquid, means for temporarily applyinga predetermined downward force to said float, means for sensing a free floating position of said float, both with said force applied at one liquid level and without said force at'a lower liquid level, means in said flow line for controlling flow therethrough and thereby causing'variations in liquid level within. said reservoir, and sensing means for determining the respective free floating positions of said float, whereby the predetermined quantity of liquid between the free-floating positions of said float-may be metered.

I WILDER ,vc. STICKNEY.

REFERENCES CITED The following references are of record inthe flle of this. patent:

UNITED STATES P ATEN'IS Number, Name Date 967,378 Hillmer Aug. 16, 1910 2,352,630

Griswold July 4, 1944 

